Two El Centro College officers were among those wounded in Thursday night's deadly shooting, changing the total of officers injured to nine, the school announced Sunday.

The officers were on patrol Thursday night when they heard gunfire on the Lamar Street side of the college. As they were responding to the exit, the glass doors exploded with gunfire, said El Centro's police Chief Joseph Hannigan.

College police officer Cpl. Bryan Shaw was hit under the vest when Micah Xavier Johnson began to shoot out the locked glass doors at the Lamar Street entrance to the college, spokeswoman Ann Hatch said in a prepared statement.

Shaw was grazed under his vest by one of the bullets as he guarded the entrance. He was treated on the scene by paramedics and returned to the scene with bullet fragments still lodged in his stomach, she said.

Officer John Abbott was also wounded when glass shattered, Hatch said.

With glass still in his legs, Abbott, a former Navy Corpsman who serves in the Naval Reserve, went immediately to try to save DART Officer Brent Thompson, who died at the scene, she said.

Abbott, who served with DART police from March 2009 until October 2015, then took care of his cuts and returned to protect others, Hatch said.

Shaw will require surgery later this week, but both officers are recovering at home with their families.

The college said it salutes its officers "for their heroic actions during this tragic event."

El Centro President Jose Adames said Johnson shot out the locked glass doors at El Centro and proceeded to the second floor of Building C, on the west side of the complex, at the corner of Elm and Market streets.

This differs from some reports, which place Johnson shooting solely from a parking garage owned by Bank of America on Lamar Street, adjacent to the east side of El Centro.

Before the end of the night, Johnson would go on to kill four more officers, wound seven Dallas police and DART officers and injure two civilians before he was killed by a bomb-carrying police robot.

Thompson, the officer Abbott attempted to save, is the first DART officer killed in the line of duty since the transit system's police force was formed in 1989.

Some students and faculty were holed up in the building during the shooting, but none were injured. Campus police were patrolling the entrances to the college as marchers walked by.

Hannigan, as well as three other officers — Luis Hernandez, Andrew Maughan and Gene Pouncy — worked the night of the shootings.

Hannigan said the officers participated with route clearings and rescues all night.

"I can't say enough about the bravery, not only of the college police officers but of the Dallas police officers," he said at a news conference Monday. "Once inside the facility we worked as one. The skill and equipment and strategy that the Dallas Police Department brought with them is amazing."

Several off-duty El Centro officers also responded shortly after the violence broke out.